(H
2
O) from inorganic fuels, for example, hydrogen, ammonia, hydrofluoric acid,
hydrochloric acid, etc.
The detector's principle of operation is based on the patented spectral analysis technology
that identifies the infrared spectral signature of fire products, namely the hot CO
2
spectral
emissions band at 4.2 to 4.7 microns and the hot water (H
2
O) spectral emission band at
2.7 to 3.0 microns. The detector also analyzes additional spectral bands (above and below
these bands) for background interferences.
The spectral analysis incorporates several detection algorithms, according to several types
of fire events, taking into account simultaneous detection of both CO
2
and H
2
O peaks or
only one of them, as well as flickering analysis at frequencies typical to these flames. Only
when all the parameters of the spectral analysis and the flickering analysis meet the
predetermined values is a fire condition identified and the fire alarm activated.
When exposed to non-fire radiation sources, these parameters do not identify a fire
condition, and the detector does not react.
1.4.2
Heated optics
The flame detector uses heated optics. The heater increases the temperature of the
optical surface by 5 to 8 °F (3 to 5 °C) above the ambient temperature to improve
performance in icing, condensation, and snow conditions.
The heated optics can be set to one of the following:
•
Off, not operating.
•
On continuously.
•
Automatic, per temperature change (default): the operator can define the start
temperature below which the window is heated. The default is 41 °F (5 °C). The
operator can define this temperature between 32 °F (0 °C) and 122 °F (50 °C). The
heating stops when the temperature is 27 °F (15 °C) above the start temperature.
For more information, see
1.4.3
HART
®
protocol
The flame detector uses the HART protocol.
HART communication is a bi-directional industrial field communication protocol used to
communicate between intelligent field instruments and host systems. HART is the global
standard for smart process instrumentation, and the majority of smart field devices
installed in plants worldwide are HART-enabled. HART is available in output configurations
1A, 2A, and 3A (see
).
HART technology is easy to use and very reliable.
Through the HART connection, you can do the following:
•
Detector setup
•
Detector troubleshooting
•
Detector health and status
Introduction
Reference Manual
June 2021
00809-0100-4976
12
Emerson.com/Rosemount
Legacy
